THIS invention relates to a rigid flange coupling, and in particular, to a partially discontinuous inner sleeve for use in such rigid flange coupling.
Rigid flange couplings are typically used to fasten or join the ends of two shafts axially in order to transmit power and torque between the two shafts.
One type of prior art rigid flange coupling comprises an outer flange defining a stepped cylindrical passage which holds an internal connection assembly to connect frictionally with the end of a shaft. The internal connection assembly comprises a discontinuous inner sleeve defining a cylindrical passage or bore to hold frictionally the end of a shaft, the discontinuous sleeve having a cut out or slit in its wall in order to assist with the alignment and fastening of the internal connection assembly onto the shaft. The outer surface of the inner sleeve defines a protruding rim with tapered surfaces extending from the protruding rim to the two ends of the inner sleeve. The internal connection assembly further comprises two annular rings with tapered inner surfaces to provide a self-locking mechanism when the two annular rings are secured on either side of the protruding rim.
One disadvantage that has been identified with the abovementioned prior art rigid flange coupling device is that, due to the cut out or slit in the wall of the inner sleeve, misalignment of the rigid flange coupling, in particular of the inner sleeve on the shaft, may occur, which may result in damage to the rigid flange coupling or alternatively, may cause an inability to secure the annular rings and sleeve to each other.
Also, it has been found that the interlocking tapered surfaces of the annular rings and inner sleeve may prevent the dismantling of the rigid flange coupling from a shaft.
South African Patent No. 2008/03992 addressed at least some of the above drawbacks by providing a partially discontinuous inner sleeve having a connecting formation that extend between an inner surface of the sleeve into a protruding ridge defined on an outer surface of the inner sleeve. A major drawback of this prior art is that during the removal of the unit the connecting formation, i.e., the remaining portion of the discontinuous split, often breaks, which makes the advantage provided by the prior art null and void as reuse of the unit is impossible.
It is an object of the present invention to address the above problems and to provide an alternative rigid flange coupling.